I see no benefit to the proposed scheme. The only reason for using terse, abbreviated tags is if you're in a context where space is at a premium: there, it would make perfect sense to have a question tagged with a bunch of three-letter codes. But we're not in such a context. We're not a 1980s database.
These tags would be hard for people to understand and hard for search engines to understand. They wouldn't help people but, in fact, they would hinder people as we'd have to add them to every question that was posted. (Even if we just applied them to new questions, I guarantee that almost every question posted would need to be corrected.) Anybody who knows what NAV means can read the word "navigation" just as quickly (adults read familiar words by pattern-matching the whole word, not by parsing the letters individually); anybody who doesn't know what NAV means is hindered by the use of it.
These tags would only work for experts – and, by that, I mean not people with expertise in aviation but people with expertise in our particular site. But, really, our site is pretty simple to use. We shouldn't need a concept of "expertise in Aviation Stack Exchange." If we need that, then the site is getting in its users' way.
This is a scheme with zero benefits and some downsides. We should not implement it.